Traction device for a unit for pulling an elongated element



Aug. 9, 1966 J GODDERIDGE 3,265,269 TRACTION DEVICE FOR A UNIT FORPULLING AN ELONGATED ELEMENT Filed Nov. 30, 1964 United States Patent3,265,269 TRACTION DEVICE FOR A UNIT FOR PULLING AN ELONGATED ELEMENTJean Godderidge, 11 Blvd. Henri Barbusse, Houilles, Seine et Oise,France Filed Nov. 30, 1964, Ser. No. 414,790 Claims priority,application France, Nov. 29, 1963, 955,440 2 Claims. (Cl. 226-172) Thepresent invention relates to a traction device for use in an apparatusfor pulling an elongated element, which device is in the form of anendless loop wrapped around the element in the manner of a screw havingmultiple threads.

It is well known that there are difiiculties involved in the pulling ofelongated elements, such as cables, when these elements are too stiff tobe wrapped on a capstan.

Various remedies for these difficulties have already been proposed. Onemay cite, for example, the suggested use apparatus of the continuoustread type, which apparatus These and other objects, features andadvantages of the present invention, will become better understood fromthe following detailed description when taken together with the attacheddrawings, in which:

FIG. 1 is a side view of a pulling apparatus of the type I describedabove;

is expensive and bulky, to mention only two of its drawbacks.

It has also been proposed to construct drawing apparatus which is bothsmall and inexpensive and in which an endless, supple pulling device isstretched between two pulleys to form a loop which is at least doubled;this device is wrapped around the element to be pulled in the manner ofa multiple-threaded screw. By causing the axes of the pulleys to rotatearound the axis of the element to be pulled and by causing the tractiondevice to move along its own axis, one causes the pulling device tounwrap from one extremity, and to wrap around the other extremity of theportion of the element around which it is wrapped. This portion of theelement moves with the pulling device and hence is pulled along the lineof its axis.

By combining the velocity of rotation of the pulley axes around the axisof the element with the velocity of movement of the pulling device, oneobtains the motion of the element to be pulled along its own axis withthis element either turning or not around its own axis.

In such a traction apparatus, it has already been suggested to use, asthe pulling device, a supple member, such as a cord, a steel cable, alink chain, or other similar means, which is generally covered with asheath of rubber, for example, which serves to increase the coefiicientof friction of the device and to avoid damaging the elements to bepulled.

Such an element presents several drawbacks the most noteworthy of whichis an inadequate gripping which produces a slippage between the pullingdevice and the element being pulled.

The present invention proposes to overcome these drawbacks by providinga particular form of pulling device which permits the effective pullingof an elongated ele' ment which may or may not be caused to twist aboutits ax1s.

The device forming the object of the present invention is intended to beused in an apparatus of the type described above and is characterised inthat it comprises, in combination: a supple central cable whose ends arejoined to form a continuous loop; a plurality of sleeves disposed alongand rigidly connected to said cable at regular intervals; and aplurality of supple, annular gripping elements having high frictionsurfaces and freely disposed on said cable alternately with saidsleeves, said gripping elements having larger outer diameters than saidsleeves.

In one preferred embodiment of the invention, the gripping elements areshaped to correspond with the shape of notches arranged in the pulleysdisposed in the apparatus, these pulleys being driven in rotation, andin turn driving the pulling device along the path defined by the axis ofits central cable.

FIG. 2 is a longitudinal cross-sectional view of a portion of :agripping device according to the present invention; and FIG. 3 is a planview of a portion of the device indicated FIG. 2 together with itsdriving pulley. The pulling machine shown in FIG. 1 comprises a frame 1which is rotatable about the axis of the elongated element 2 which is tobe pulled in the direction of arrow f. Frame 1 carries, at one of itsends, two return pulleys 3a and 3b and two guide pulleys 4a .and 4b. Atits other end, the frame carries a second pair of guide pulleys 5a and5b and two driving pulleys 6a and 6b. These driving pulleys are eachrigidly connected to a respective one of the pinions 7a and 7b engaginga conical pinion 8.

Between these various pulleys is passed .a pulling device 9 which isconstituted, in the prior art, by an endless cable wrapped around theelement to be pulled in the manner of a multiply-threaded screw. Eachelement of the cable passes the pulleys in the following order: 6a, 5a,4a, 3a, 6b, 5b, 4b, 3b and 6a.

When the frame is driven in the direction of arrow F (counter-clockwiseif one were to view the machine from the left of the figure), with theaid of any well-known driving means (not shown), the device 9 wraps onto the element 2 at the end of the frame removed from pinion 8 andunwraps therefrom at the other end of the frame. At the same time, theportions of cable 9 which are wrapped around the element 2 are driven inthe direction of the cable axis by pinions 7a and 7b, thus pullingelement 2 in the direction of arrow 1.

It is known that, with the pinion 8 being maintained motionless, aproper choice of both the gear ratio between the pinions and of thediameters of the driving pulleys 6a and 6b enables the element 2 to bepulled in the direction of arrow 1 without experiencing any twistingabout its own axis. Equally, if the various parts of the apparatus havethe above-described dimensions and pinion 8 is rotated at a rate N, theelement 2 will move in the direction of arrow f while turning about itsown axis at a rate N.

It thus results that the apparatus can pull an elongated element whilecausing it either to turn or not about its own axis.

In the prior art device 9 has usually been constituted by a metalliccable whose ends are joined together and which is covered by a sheath ofa material such as rubber.

FIGS. 2 and 3 show .a pulling device and pulley according to the presentinvention correspond, in function, to device 9 and, for example, pulley6a of FIG. 1.

The pulling device of this invention, designated in general by referencenumeral 19, is composed of a central core 20 constituted, for example,by a metallic cable.

Upon this core are fixed spaced sleeves 21a to 21n. The two ends of thecore are joined together by any known means such as the junction sleeve22.

Annular elements 23a to 23n are slid onto cable 20 so as to alternatewith sleeves 21a to 2121. These elements are free to rotate with respectto core 20 and the sleeves 21, but are prevented from movinglongitudinally of core 20 by the abutment of said sleeves.

Elements 23a to 2311 are made of a relatively supple material, such asrubber, having a suitable coeflicient of friction.

Device '19 is moved along the path described by its longitudinal axis byat least one notched pulley 24, with elements 23 coming to lodge in thenotches of the pulley when this pulley is driven in rotation.

One pulley 24 is intended to replace at least one of the pulleys 6a and6b of FIG. 1 and to be rigidly connected to one of the gears 7a and 7bwhich engages pinion 8.

Pulling device 19 is substituted for the device 9 of FIG. 1, is wrappedaround the element 2 and bears thereagainst through the intermediary ofelements 23.

The apparatus thus modified functions in exactly the same manner as thatdescribed in connection with FIG. 1.

It has been observed that an apparatus furnished with the means of thepresent invention performs the pulling operation in a highlysatisfactory manner, equally well when the element 2 rotates about itsaxis or not. This improved result is believed to be due to the improvedability of the engaged surfaces 23 of the portion of the cable wrappedaround element 2 to conform to the shape of the element.

While one preferred embodiment of the present invention has been shownand described herein, it should he appreciated that many variations andmodifications may be given thereto without departing from the spirit ofthis invention and that its coverage should therefore be limited only bythe scope of the appended claims.

What I claim is:

1. A device for use in a traction apparatus for pulling an elongatedelement, said apparatus comprising a frame rotating about the aXis ofthe element to be pulled and carrying a plurality of pulleys for guidingand driving said device in a path defined by its longitudinal axis, saiddevice being intended to have the form of a doubled loop which iswrapped around said element in the manner of the multiple threads of ascrew so that the portions of said device which contact said elementmove in the direction of the longitudinal axis of said element, and urgesaid element in this direction, characterized in that said devicecomprises in combination: a supple central cable whose ends are joinedtogether to form a continuous loop; a plurality of sleeves disposedalong, and rigidly connected to said cable at regular intervals; and aplurality of supple, annular gripping elements having high frictionsurfaces and freely disposed on said cable alternately with saidsleeves, said gripping elements having larger outer diameters than saidsleeves.

2. A device according to claim 1, characterized by the fact that saidgripping elements are shaped to correspond with the shape of notchesarranged in at least one driving pulley of said apparatus.

References Cited by the Examiner UNITED STATES PATENTS SAMUEL F.COLEMAN, Primary Examiner.

1. A DEVICE FOR USE IN A TRACTION APPARATUS FOR PULLING AN ELONGATEDELEMENT, SAID APPARATUS COMPRISING A FRAME ROTATING ELEMENT, SAIDAPPARATUS COMPRISING A FRAME CARRYING A PLURALITY OF PULLEYS FOR GUIDINGAND DRIVING SAID DEVICE IN A PATH DEFINED BY ITS LONGITUDINAL AXIS, SAIDDEVIDE BEING INTENDED TO HAVE THE FORM OF A DOUBLED LOOP WHICH ISWRAPPED AOUND SAID ELEMENT IN THE MANNER OF THE MULTIPLE THREADS OF ASCREW SO THAT THE PORTIONS OF SAID DEVICE WHICH CONTACT SAID ELEMENTMOVE IN THE DIRECTION OF THE LONGITUDINAL AXIS OF SAID ELEMENT, AND URGESAID ELEMENT IN THIS DIRECTION, CHARACTERIZED IN THAT SAID DEVICECOMPRISES IN COMBINATION: A SUPPLE CENTRAL CABLE WHOSE ENDS ARE JOINEDTOGETHER TO FORM A CONTINUOUS LOOP; A PLURALITY OF SLEEVES DISPOSEDALONG, AND RIGIDLY CONNECTED TO SAID CABLE AT REGUALR INTERVALS; AND APLURALITY OF SUPPLE, ANNULAR GRIPPING ELEMENTS HAVING A HIGH FRICTIONSURFACES AND FREELY DISPOSED ON SAID CABLE ALTERNATELY WITH SAIDSLEEVES, SAID GRIPPING ELEMENTS HAVING LARGER OUTER DIAMETERS THAN SAIDSLEEVES.